#模式 a 追加，内容结尾处追加新内容
with open('./files/test.txt','a',encoding='utf-8') as f:
    f.write('这是追加的内容1\n')
    f.write('这是追加的内容2\n')
    f.write('这是追加的内容3\n')

with open('./files/test.txt','r',encoding='utf-8') as f:
    print(f.read())